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Increase of Flow Rate of Super - Mini Sac Nozzle and its Application for General Use Small Engine 1999-01-3263

Reacent strict emisssion regulation requires inprovement in the contradictory turget, that is to say, more engine power per displacement and less pollutants. This target could be realized ZEXEL by increasing the allowable injection quantity in the nozzle with a smaller sac volume, and increasing the flow rate of nozzle hole without enlarging the nozzle orifice size.

Sac volume of the super-mini sac nozzle is dereased to 0.17mm3, from 0.23-0.31 mm3 which is the minimum level of the conventional mini sac nozzle. Increase in injection flow rate was obtained by means of the “Extrude Horn” treatment which makes round and smooth both inner surface of the sac and the entrance edge of the orifice. The trade-off between NOx, HC emissions and the combustion noise was improved by optimizing the injection rate in low speed and low load range.